[quote=@Reflection]
[@Parallel Hearts] I'm going to talk to my Co-GMs about whether we want to deal with Lancer Artoria. Mostly because she exists pretty much as a Fate/Go gatcha creation, and arguably shouldn't even be summon-able in any regular (Or even special circumstances) grail war due to how she's more or less an immortal divine spirit. It can't even really be argued as a lostbelt situation. Since Lancer Artoria is just a thin guise of her Lion King variant from Go. (And that's not even bringing up all the other special stuff she can do as a lancer.)
I suggest looking into a less controversial character idea. 
[/quote]

That's not correct. Regular Lancer Artoria is an even more viable possibility than most of the Lost Belt related material. You may be congealing her image too much with the Lion King who was an irregular entity that:

[hider=FGO Camelot Spoilers]
Survived for centuries as a consequence of Bedivere's inability to cast Excalibur back and thus was invested with an unbelievable amount of power that goes far beyond her regular Lancer version, becoming the Goddess of Rhongomyniad seen in the Camelot chapter.
[/hider]

The summonable version, such as this one, isn't the same as the Lion King in any manner which is evident from both her in game description and dialogue. To begin with this one is a pretty compassionate and caring individual, that alone should be enough to not mix her up with the alternative version.

I can give up on her if you still don't want this Servant around, but the reasons you pointed are flawed. I guess that an explanation and appeal for you to check her description in the source material is the only thing I can do now.